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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 180404A: Enhanced Swift-XRT position
  2. GRB 180404A: VLT/X-shooter redshift
  3. GRB 180404B: Swift detection of a burst with an optical counterpart
  4. GRB 180404A: Swift detection of a burst with an optical afterglow
  5. Konus-Wind observation of GRB 180402A
  6. GRB 180402A: Swift/UVOT Upper Limits
  7. GRB 180402A: Swift-XRT refined Analysis
  8. GRB 180402A: Fermi GBM detection
  9. GRB 180402A, Swift-BAT refined analysis
  10. GRB 180402A: KAIT Optical Upper Limit
  11. GRB 180402A: RATIR Upper Limits
  12. GRB 180402A: LCO McDonald observations
  13. GRB 180402A: Swift detection of a possibly short burst
  14. GRB 180331B: Swift/UVOT Upper Limits
  15. GRB 180331B: Swift-XRT refined Analysis
  16. GRB 180331B: AbAO optical observations
  17. GRB 180331B: Swift-BAT refined analysis
  18. GRB 180331B: Enhanced Swift-XRT position
  19. GRB 180331A: Swift-BAT refined analysis
  20. GRB 180331B: Swift detection of a burst
  21. GRB 180331A: Swift-XRT refined Analysis
  22. GRB 180329B: LCO FTS observations
  23. GRB 180331A: Swift/UVOT Upper Limits
  24. GRB 180331A: Enhanced Swift-XRT position
  25. GRB 180331A: Swift detection of a burst
  26. GRB 180329B: VLT/X-shooter spectroscopic observations
  27. GRB 180329B: Swift-BAT refined analysis
  28. GRB 180329B: Swift/UVOT Detection
  29. GRB 180329B: RATIR Optical Observations
  30. Swift Trigger 819863 is not a GRB
  31. GRB 180329B: NOT optical afterglow detection
  32. GRB 180329A: Swift-BAT refined analysis
  33. GRB 180329B: Swift-XRT refined Analysis
  34. GRB 180329B: Enhanced Swift-XRT position
  35. GRB 180329B: Swift detection of a burst with an optical afterglow
  36. GRB180325A: AstroSat CZTI detection
  37. Swift Trigger 819301: possible GRB 180329A
  38. GRB 180325A: VLT/X-shooter spectroscopic observations
  39. Konus-Wind observation of GRB 180318A
  40. Konus-Wind observation of GRB 180326A
  41. Konus-Wind observation of GRB 180317A
  42. GRB 180325A: further NOT observations
  43. IPN Triangulation of GRB 180326A (long)
  44. GRB 180325A: Swift/UVOT Detection
  45. Konus-Wind observation of GRB 180316A
  46. Konus-Wind observation of GRB 180324A
  47. Konus-Wind observation of GRB 180325A
  48. GRB 180325A, Swift-BAT refined analysis
  49. GRB 180325A: GROND observations
  50. GRB 180325A: Global MASTER-Net OT prompt observations
  51. GRB 180325A: TAROT Calern observatory optical observations
  52. GRB 180325A: D50 early optical follow-up
  53. GRB 180325A: Swift-XRT refined Analysis
  54. GRB 180325A: Enhanced Swift-XRT position
  55. GRB 180325A: Optical Photometry with SLKT
  56. GRB 180325A: RATIR Optical Observations
  57. GRB 180325A: prompt REM optical/NIR detection
  58. GRB 180325A: NOT redshift
  59. GRB 180325A: prompt LT observations
  60. GRB 180324A, Swift-BAT refined analysis
  61. GRB 180325A: Swift detection of a burst with an optical counterpart
  62. GRB 180324A: Swift/UVOT Upper Limits
  63. GRB 180324A: Swift-XRT refined Analysis
  64. GRB 180324A: Enhanced Swift-XRT position
  65. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
  66. GRB 180324A: KAIT Optical Upper Limit
  67. GRB 180324A: Prompt enhanced Swift-XRT position
  68. GRB 180324A: Swift detection of a burst
  69. IBAS Alert n. 8033: Not a GRB
  70. IPN Triangulation of GRB 180318A (long)
  71. IPN Triangulation of GRB 180317A (short/hard)
  72. IBAS Alert n. 8032: Not a GRB
  73. GRB 180316A: RATIR Optical Observations
  74. GRB 180316A: MITSuME Akeno optical upper limits
  75. GRB 180316A: MITSuME Okayama optical upper limits
  76. GRB 180316A: TSHAO optical observations
  77. GRB 180314A: AstroSat CZTI detection
  78. GRB 180316A: RATIR Optical Observations, Possible Re-brightening
  79. Konus-Wind observation of GRB 180314A
  80. GRB 180316A: Swift-BAT refined analysis
  81. GRB 180316A: Swift-XRT refined Analysis
  82. GRB 180316A: Swift/UVOT Detection
  83. GRB 180316A: RATIR Optical Observations
  84. GRB 180316A: Enhanced Swift-XRT position
  85. GRB 180316A: LCO Cerro Tololo observations
  86. GRB 180314A: MITSuME Okayama optical upper limits
  87. GROND observations of GRB 180316A
  88. GRB180316A: MASTER-IAC OT light curve
  89. GRB180316A: MASTER-IAC optical detection
  90. GRB 180316A: Prompt enhanced Swift-XRT position
  91. GRB 180316A: Swift detection of a burst
  92. GRB 180314B: RATIR Optical Observations
  93. GRB 180314B: Swift-BAT refined analysis
  94. GRB 180314B: Zeiss-1000/CrAO optical upper limit
  95. GRB 180314B: Swift/UVOT Upper Limits
  96. GRB 180314B: Swift-XRT refined Analysis
  97. GRB 180314B: Enhanced Swift-XRT position
  98. GRB 180313A: Fermi GBM detection
  99. GRB 180314B: Prompt enhanced Swift-XRT position
  100. GRB 180314B: Swift detection of a burst

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